FR-A1-2 997 681 proposed a new aircraft architecture which makes it possible to reduce the noise pollution and fuel consumption of the aircraft by limiting the aerodynamic drag through absorption of the boundary layer.
In such an architecture, an aircraft is propelled by a turbine engine having ducted contra-rotating fans, the turbine engine being integrated at the rear of the fuselage of the aircraft. Generally, the turbine engine comprises two gas generators which feed a power turbine having two contra-rotating rotors for driving two fans arranged downstream of the gas generators. The gas generators have distinct lateral air intakes to feed each of them. Downstream of the gas generators, the fans are arranged in the extension of the fuselage of the aircraft and are generally powered by an annular ring connected thereto so as to absorb at least some of the boundary layer formed around the fuselage. The diameter of the fans is approximately the same as that of the fuselage where the cross section thereof is greatest. The rotational speed of the fans is generally lower than for conventional turbine engines, in particular so that the speed at the blade tip is subsonic.
DE 3834511 A proposed a fan propulsion device comprising two contra-rotating propellers, each rotated by an engine. The two engines are coaxial, and if one of the two engines fails, the fan stops, and the other fan continues to operate.
However, the possibility of one of the fans malfunctioning, for example becoming imbalanced, or even losing a blade, must be taken into account. In this case, even if the engine is not malfunctioning, the fan rotor must be shut down to allow the aircraft to return to an airport.
The object of the present disclosure is to propose a way of shutting down the rotor so as to have the best possible operating conditions in this downgraded mode for returning to an airport.
A secondary object of the disclosure is to determine when the malfunctioning rotor must be shut down.